In recent years, portable terminal devices used for mobile communication have been made smaller and lighter, and as they have been made multiband and multifunctional to cope with a plurality of communication systems, the number of circuits incorporated therein increases. For this reason, it is strongly desired that electronic components to be used therein should be made surface-mountable and smaller in order to increase packaging density.
One of key parts of the portable terminal devices is a surface acoustic wave device. The surface acoustic wave device usually has a construction in which a sealed hollow portion serving as a vibration space is provided in vicinity of an electrode surface exciting a surface acoustic wave. Also for such a surface acoustic wave device, it is required to be made surface-mountable and smaller.